In a subsea installation or subsea application, such as an oil or gas exploration and conveying application, there may be a need for heating pipelines which convey the gas or the oil to prevent clogging due to the generation of hydrates within the conveyed carbohydrates including oil and/or gas. This clogging or aggregation of hydrates within the pipeline may occur both during operation, i.e. flow of the carbohydrates, and in particular at a steady state or at still-stand.
Conventionally, to prevent the hydrates from being clogged chemicals have been injected into the manifold or the pipeline. Alternatively, a direct electrical heating (DEH) system has been installed, wherein the electric power has been provided from a topside facility, i.e. a facility which is located above the sea level. The direct electrical heating may heat a pipeline by running an electric current through the pipeline which evolves, when ends of the pipeline are connected to two terminals of a 1-phase power source.
Document WO 2006/075913 A1 discloses a system for power supply to subsea installations, wherein a power supply cables are for direct electrical heating of a pipeline and the system is further configured, to provide a 3-phase power supply to an electrically powered motor in a subsea installation unit, wherein means are arranged for switching so that the three conductors forming the power supply cables form parallel conductors in a second circuit configuration, wherein the power supply cables supply power for direct heating of the pipeline.
It has been observed that supply of the 1-phase power stream from a topside facility to the direct electrical heating system is very cumbersome and difficult and involves hampering the performance of the system.